abstract class Shape{

    public abstract void draw();

}

class Rect extends Shape{
    public void draw(){
        System.out.println("Rect");
    }
}
class Cycle extends Shape{
    public void draw(){
        System.out.println("Cycle");
    }
}
public class Main {

    public static void main(String[] args) {

        System.out.println("Hello world!");
    }
}